Technical Field of the Invention
The present invention relates, generally, to alkali silicate glasses which are used as the basic glasses for the manufacture of selective filter glasses. More particularly, the present invention relates to the manufacture of selective filter glasses, colored with Co.sup.2+ or with Co.sup.2+ and Ni.sup.2+, which have transmission ranges primarily in the ultraviolet and visible spectral region between 280 and 500 nanometers (nm). These ion-colored glasses are imbued with the characteristic absorption bands of Co.sup.2+ and Co.sup.2+ together with Ni.sup.2+ and, therefore, depending upon the layer thickness, produce selective bell-shaped transmission ranges, each surrounded by two stop ranges.